1. Field of the Invention
The present invention relates in general to seat sliding devices of motor vehicles, and more particularly to the seat sliding device of a power type which can slide the seat to a desired position with an electric power. More specifically, the present invention is concerned with the power seat sliding device which can exhibit a satisfied durability against big shock applied thereto due to a vehicle collision or the like.
2. Description of the Prior Art
Hitherto, various power seat sliding devices have been proposed and put into practical use particularly in the field of motor vehicles. For providing the devices with a satisfied durability against a big shock applied thereto due to a vehicle collision or the like, various measures have been hitherto taken.
One of conventional power seat sliding devices having a certain durability against such shock is shown in Japanese Patent First Provisional Publication 6-336130. The power seat sliding device of this publication comprises generally a pair of lower rails fixed to a vehicle floor, a pair of upper rails slidably engaged with the lower rails and supporting thereon a seat, a drive shaft rotatably held by one of the upper rails and having a spiral groove formed therearound, an electric motor carried by the upper rails for driving the drive shaft, and a nut member fixed to one of the lower rails and operatively engage with the drive shaft.
Thus, when the electric motor is energized to rotate the drive shaft in one or other direction, the upper rails and thus the seat are moved forward or rearward on the lower rails to a desired position.